Water pump impeller having electrical insulation and corrosion-preventative features

ABSTRACT

An impeller for rotary water pumps and the like which through the provision of novel components and combinative relations with the driving shaft of an electric motor, inherently accomplishes two important new results, to wit: 1. The housing of the pump and all water passing therethrough are dielectrically insulated from the metal driving element of the motor. 2. The motor shaft, from its terminal point to an area outside of the pump housing, is entirely enclosed within a protruding sleeve carried by the impeller, thus preventing accumulation of rust or other corrosion as well as eliminating electrolytic buildup on the motor shaft.

Y United States Patent [72] Inventor William A. ()den Temple City,Calif.

[21] Appl. No. 848,829

[22] Filed Aug. 11, 1969 [45] Patented July 20, 1971 [73] AssigneeDomain Industries, Inc.

New Richmond, Wis.

[54] WATER PUMP IMPELLER HAVING ELECTRICAL INSULATION ANDCORROSlON-PREVENTATIVE FEATURES 4 Claims, 3 Drawing Figs.

[52] US. Cl 417/423, 277/96 [51] Int. Cl ..F04b 35/04, F16j 15/54 [50]Field of Search 103/103, 114; 41 7 423; 277/96 x [56] References CitedUNITED STATES PATENTS 2,759,428 8/1956 Kirby 103/103 2,764,099 9/1956Wernert 103/114 X 3,003,424 10/1961 Prasse 103/103 (M) 3,168,868 2/1965Schulty... 103/87 3,264,999 8/1966 Tutthill 103/87 3,304,875 2/1967Copeland 103/87 Primary Examiner-Leonard H. Gerin Attorneys-Williamson,Palmatier & Bains, George F.

Williamson, l-l. Dale Palmatier and Herman H. Bains ABSTRACT: Animpeller for rotary water pumps and the like which through the provisionof novel components and combinative relations with the driving shaft ofan electric motor, inherently accomplishes two important new results, towit:

1. The housing of the pump and all water passing therethrough aredielectrically insulated from the metal driving element of the motor.

2. The motor shaft, from its terminal point to an area outside of thepump housing, is entirely enclosed within a protruding sleeve carried bythe impeller, thus preventing accumulation of rust or other corrosion aswell as eliminating electrolytic buildup on the motor shaft.

PATENTED M20197] 3, 594. 102

, INVENTOR. MAL/4M 4 0051/ WATER PUMP IMPELLER HAVING ELECTRlCALINSULATION AND CORROSION-PREVENTATIVE FEATURES The invention ischaracterized by the combination with a water pump housing which has agenerally central liquid chamber, an intake, a discharge, and an axialsleeve at one end for accommodation of the rotary driving or motor shaftas well as the mechanical annular seal assembly, of the novel rotaryimpeller with its blades mounted in the liquid chamber and with a backbodyplate having a rigid axial portion constructed wholly of electricalinsulating material. Preferably the entire backplate and impeller areconstructed of electrical insulating material. The axial portion hasrigidly connected thereto and sealed therewith (preferablyjntegrallyformed) a rearwardly protruding coaxial protective sleeve constructedalso of electrical insulating material. This sleeve snugly surrounds theend of the driving shaft.

This invention relates generally to rotary impellers employed incombination with the housing of conventional types of water pumps, andwhich have provision for accommodating the projecting end of the drivingor armature shaft of an electric motor, and in addition, provide forretaining and accommodating a mechanical sealing assembly interposedbetween the motor driving shaft and a flange or sleeve provided by therear end of the pump housing.

In the prior art, water pumps of the class described directly driven andinterconnected with the driving shaft of an electrical motor, areextensively used for a variety of purposes including numerous uses wherethe water discharged from the pump engages the person of a human being,such as in supply to swimming pools, household water systems, lavatoriesand the like. In motor-driven water pumps of such types, there has beenalmost universally the critical danger of electrical curliquid betweenthe mechanical seal assembly and the outer portion of the motor shaftwhich passes therethrough. Thus, rust and other corrosion as well asaccumulation of materials through electrolytic action, has often inextended use of the waterpump caused the motor shaft and the mechanicalseal to become interlocked.

lt isan object of my present invention to provide in conventional waterpump housing with a water chamber and intake (usually axial), and withan axial sleeve atone end of the housing for accommodating the motordriving shaft and an annular seal assembly, a novel and improved rotaryimpeller which employs certain new components closely cooperating withparts of a conventional pump housing to dielectrically insulate themetal motor driving shaft-from the housing and impeller of the pump, andfrom the water or other electrical conductive liquid passing through thepump.

A further object is to provide a pump impeller which through itsinherent components, provides a protective seal completely surroundingand encasing the extremity of the motor driving shaft and portionsextending into the pump housing, thereby positively eliminating contactof the motor shift with any water or other conductive material andpreventing accumulation of rust or other corrosion'as well as collec''tion of any material which might result from an electrolytic actionupon the motor shaft or upon the seal assembly which surrounds theshaft. 1

More specifically, it is an object of my invention to provide incombination with a water pump housing of the type having a central waterchamber and an intake and discharge, as well as an axial sleeve or thelike at one end for receiving and accommodating the driving shaft of themotor together with a mechanical seal assembly, a closely cooperating,novel rotary impeller which in addition to a body or backplate andblades, rigidly carries and preferably has formed integral therewith, aclosed socket in the form of a sleeve closed at its inner end andconstructed of electrical insulating material and dimensioned to snuglyfit the projecting outer end of the motor driving shaft, whollyenclosing the same. The structure of the rotary impeller further, at theinner end of the sleeve where the axial portion of the backplate of theimpeller is integrally constructed of electrical insulating material,contains a driven element for positive driving connection with theterminal portion of the motor shaft.

The foregoing and other objects of the invention will be I more apparentfrom the following description made in conjunction with the accompahyingdrawings, wherein like reference characters refer to similar partsthroughout the several views and in which: 7

FIG. 1 is a horizontal cross section taken axially through the ratherconventional type of water pump housing, with an embodiment of myimpeller invention operatively employed and drivably connected with theprojecting driving shaft of an electrical motor;

FIG. 2 is a front elevation or front plan view of the impeller detached,some portions being broken away to disclose certain elements disposedrearwardly of the axial portion of the impeller;

FIG. 3 is a cross section looking in the direction of the arrows takenon the line 3-3 of FIG. 1.

In the embodiment of the invention illustrated, my novel impeller andrelated components are shown, operatively employed in the housing ofconventional structure for a water pump which comprises a pair ofinterconnected and opposed frustoconical housing sections H-1 and H-2,sealed and secured together along their peripheral edges. The rearsection H-l of the pump housing is provided with a concentric axialsleeve 5 of conventional structure, having an internal angular shoulder50 which assists in retaining a conventional annular sealing assembly A,which in structures of the prior art, directly surrounds the drivingshaft S of the electrical motor M.

It will be understood that in-this structure, the motor driving shaft Sat its projecting end, is accommodated in the recessed portion of thehousing sleeve 5, disposed coaxially thereof and of course, coaxiallywith the impeller which is employed in combination with the pump housingand its intake and discharge structure.

Referring again to the housing sections H-1 and l-l-2, adjacent theircircular peripheral edges, they are provided with a groove 6, shoulder 7respectively, for receiving and clamping against a large sealing ring orgasket 8. The two housing sections H-l and H2 are clamped together aboutthe sealing ring 8, by suitable clamping bolts or other means, notshown.

My impeller, indicated as an entirety by the letter i is preferably, butnot necessarily, integrally constructed with all its components andrelated parts, from hard dielectric or electrical insulating materialsuch as for example, polycarbonate. The entire impeller structure may beinjection molded from suitable plastic material such as polycarbonate. Aspecific example of suitable-polycarbonate material which'resists wear,has high tensile strength and suitable rigidity and resistance tofracture or splitting, is the material known as Lexan" supplied byGeneral Electric Company. In the form shown, my impeller comprises asubstantially rigid, circular backplate 10, provided with a preferablyintegral reinforced axial and forwardly indented portion 10a, which ifmolded integrally with the backplate 10 is thickened in structure.

Projecting and protruding rearwardly and axially from the eye portion isa preferably integrally formed, protective cylindrical sleeve 11 whichmust, of necessity, as well as the portion 10a, be constructed ofsubstantially hard, smooth electrical insulating material. Sleeve 11 isrigidly secured (preferably integrally formed) with axial backplateportion 10a and is internally dimensioned to smoothly and snuglytelescope with and surround the motor driving shaft S, enclosing thedrive connection end 8-1 of said shaft.

In the injection or other fabrication of the socket formed by the innerend of protective tube 11 and the concave portion 10a of the eye ofimpeller back disc 10, an internal, shaped drive connector element, suchas a metal insert thimble 12, is positively affixed as by embedding inthe plastic material of eye 10a and sleeve 11, and internally and snuglyinterfits with the end S-l of motor shaft S. In the form shown in F IG.1 of the drawings, the drive connection end S-l of the motor is providedwith a longitudinal spline -2. A diagonally disposed setscrew X isthreaded to a tapped opening in the insert thimble l2 and its inner endengages and is locked in the spline S-Z. After insertion of the setscrewX, plastic sealing material covers the head and tapped aperture in theportion a of the impeller through which the setscrew is applied.

it will of course be understood that the insert thimble 12 may beotherwise drivably connected to the end 5-! of motor shaft S, such as bybeing formed with internal threads which engage with external threadsprovided by the extremity of the motor shaft.

in the preferred form, an annular flange 13 (preferably integrallyfonned with the backplate 10 of the impeller), constructed of hardelectrical insulation material, is positively affixed to the rear faceof back disc 10 and disposed in spaced relationship concentric of theprotective sleeve 1 1. This annular flange 13 is adapted to receive andfrictionally retain the forward cylindrical portion of a mechanical sealassembly which preferably is provided with an annulus A-l constructed ofelectrical insulating material. The sealing unit A-l, which includes theexternal annulus, has affixed thereto an annular sealing element 20 of acomposition to form an efficient seal and which is very slightlycompressible, said part 20 extending rearwardly a slight distance beyondthe forward edge of the annulus A-l for contact with a cooperatingsealing element, later to be described.

The sealing assembly utilized, which is of conventional structure,includes a second sealing unit A-Z for retention internally in the rearannular sleeve 5 and with the assistance of the shoulder 5a of saidsleeve. The unit A-2 comprises a light metal generally annular shellmember 21 and a spring-pressed ring 22 constructed of electricalheat-insulating material with a coil spring 23 interposed between theannulus 21 and the ring 22 urging the ring at its inner planar bearingsurface into firm contact with the element 20 carried by the opposingsealing unit A-l. The interior surfaces of units A] and A-2 are spacedslightly outwardly of the protective sleeve 1 1.

On the front face of the circular impeller backplate 10, impeller blades14 and are, as shown, successively formed, preferably being integrallymolded from the material of backplate l0, and protruding forwardly fromthe backplate, shaped in substantial radial and longitudinalconfiguration for closely clearing the interior of the forward housingsection H-2.

The backplate l0 and impeller blades 14 and 15 revolve in the mainliquid chamber, designated by the letter C, within the pump housing.Housing section H2 has an axial intake 16.

While the blade formation and arrangement of my impeller may take a widevariety of forms, in the particular embodiment illustrated in FIG. 2 ofthe drawings the longer impeller blades 14 have their inner endsextending inwardly slightly beyond the cross-sectional area of the fanintake 16, while the shorter blades 15, at their inner ends, terminate aspaced distance from the impeller backing plate proper. The tips ofblades 14 'and 15 are disposed in close working clearance to the maininternal circumference of the water chamber C mainly defined by thehousing section H-2. in conventional fashion a tangential andcentrifugal discharge passage 17 is defined by the configuration andstructure of the housing section H-Z.

if desired, a disc 24, constructed preferably of dielectric material,may be affixed to the outer end portion of protective sleeve 11 and ofcourse will revolve therewith to further exelude dust and prevent anyslight seepage of water from contact with the inner portion of shaft S,thus further preventing corrosion.

Operation separated from housing section H-l and the novel impellerl isthen axially inserted, carrying in the socket formed by the inner end ofprotective sleeve 11 and the concave portion 10a of the impeller l, theinternally squared or polygonal cross section drive connection element12. The protective sleeve 11 snugly embraces and may be driven upon theprojecting motor shaft portion S and the impeller is turned until propernonrotative seating of the driving end 8-] of the motor shaft with thethimble element 12 is obtained. In such position the protective sleeveand also shaft S extend nonnal or in perpendicular relation to the backdisc or plate 10 of the impeller, and the open end of protective sleeve11 projects preferably some little distance beyond the external end ofthe heavy axial sleeve 5 carried by the housing section H4.

The two units A4 and A-2 of the mechanical sealing assembly A arepreferably respectively seated and retained in the dielectric annularflange 13 of the impeller and internally in the sleeve 5 andinengagement with the shoulder 50 of the housing member H-l. in properseated position, the opposing edges of the seal member 20 and thedielectric seal member 22 are in contact.

It will be seen that the entire projecting portion of the motor driveshaft S is covered and enclosed by the protective sleeve 1 l and itsrigid afi'ixation and sealing with the concave surface or eye portion 10of the impeller. Since the materials or substance of said sleeve and eyeportion and axial portion [0a of the impeller are by the requirements ofthis invention constructed of dielectric or highquality electricalinsulating material, it is not possible for electromotive forces orcurrents to pass from the steel or other motor driving shaft S to anyparts of the housing of the pump structure, or to in any way beconducted to the water or other electric conductive liquid which passesthrough the pump or its central liquid chamber C.

Therefore the housing of the pump structure, as well as the contents ofall water or conductive liquid passing through the pump, aredielectrically insulated from all electromotive forces or electriccurrent.

Furthermore, it will be seen that no water from the central chamber Cmay leak through or be received by the external periphery or any portionthereof of the driving extension S of the motor shaft. This positivelyprevents any electrolytic action from taking place upon the externalperiphery of driving shaft S, as well as the production of corrosion orrust upon said shaft.

It is further pointed out that the sealing assembly comprising the unitsA1 and A-2 are electrically insulated as to all of their parts by meansof the seal-retaining flange 13, which concentrically is spaced from theprotective sleeve 1 1.

From the foregoing description it will be seen that l have not onlyprovided a new combination of impeller, components and pump structurefor overcoming serious and dangerous characteristics of the prior art;but i have further provided an inherent and preferably integral impellerstructure which may be readily employed with many types of motor-drivenpump housings now in use to produce highly desirable new results.

The construction of my unique impeller with its added components lendsitself to very economical manufacture in integral form by injectionmolding of hard plastic material such as polycarbonate.

What [claim is:

1. In use with a liquid pump housing having a generally central liquidchamber, an intake, a discharge, and an axial bore at one end foraccommodating a rotary driving shaft and a mechanical annular sealassembly,

a rotary impeller having blades mounted in said liquid chamber andhaving a back bodyplate provided with a rigid axial portion constructedwholly of electrical insulating material, said axial portion havingrigidly connected thereto and sealed therewith a rearwardly protruding,coaxial protective sleeve constructed also of electrical insulatingmaterial,

said sleeve snugly surrounding the end of said driving shaft throughoutsaid bore and having adjacent its inner end and in conjunction with saidrigid axial portion, means for drive connection of the end of saiddriving shaft with said impeller.

2. The structure set forth in claim 1 wherein,

said axial portion of said bodyplate and said sleeve are integrallyconstructed of a hard plastic material having 1 electrical insulatingproperties. 3. The structure and combination set forth in claim 1wherein,

said axial portion also has rigidly connected thereto and sealedtherewith a rearwardly protruding annular sealreceiving flange,constructed also of electrical insulating material, extending coaxialwith said protective sleeve but of substantially less length, saidsleeve having an internal cylindrical surface and said mechanical sealassembly at its forward portion being held and disposed beneath saidannular flange. 4. The structure and combination set forth in precedingclaim 3 wherein,

said back bodyplate, said axial portion, said sleeve and said annularflange are all integrally constructed of electrical insulating material.

1. In use with a liquid pump housing having a generally central liquidchamber, an intake, a discharge, and an axial bore at one end foraccommodating a rotary driving shaft and a mechanical annular sealassembly, a rotary impeller having blades mounted in said liquid chamberand having a back bodyplate provided with a rigid axial portionconstructed wholly of electrical insulating material, said axial portionhaving rigidly connected thereto and sealed therewith a rearwardlyprotruding, coaxial protective sleeve constructed also of electricalinsulating material, said sleeve snugly surrounding the end of saiddriving shaft throughout said bore and having adjacent its inner end andin conjunction with said rigid axial portion, means for drive connectionof the end of said driving shaft with said impeller.
 2. The structureset forth in claim 1 wherein, said axial portion of said bodyplate andsaid sleeve are integrally constructed of a hard plastic material havingelectrical insulating properties.
 3. The structure and combination setforth in claim 1 wherein, said axial portion also has rigidly connectedthereto and sealed therewith a rearwardly protruding annularseal-receiving flange, constructed also of electrical insulatingmaterial, extending coaxial with said protective sleeve but ofsubstantially less length, said sleeve having an internal cylindricalsurface and said mechanical seal assembly at its forward portion beingheld and disposed beneath said annular flange.
 4. The structure andcombination set forth in preceding claim 3 wherein, said back bodyplate,said axial portion, said sleeve and said annular flange are allintegrally constructed of electrical insulating material.